Rotary switch



United States ROTARY swrrcrr Max Oherholzer, Liehefeld, near Bern, Switzerland, as-

signor to Master A. G. Werire fiir Telephonie and Prazisionsmeclranik, Bern, Switzerland Application March 16, W54, Serial No. 416,546

Claims priority, appiication Switzerland l darch 39, 1953 15 Claims. (Cl. Eddd) In the case of the conventional rotary switches it is a however not possible to change or add circuit elements such as contacts or cams without the switch having to be removed from service and at least partially disassembled and reassembled. Moreover, the individual switching units of the conventional. types require comparatively a great deal of space. The present invention overcomes these disadvantages.

in the cam switch of the present invention, individual operating cams may be removed and replaced at will without dismounting their common operating shaft or removing other cams on the shaft and individual switch units may be similarly removed and replaced at will without disturbing other switch units, except for such turning of their common operating shaft as may be required to bring it to a predetermined angular position during i the changing of cams. When changing switch units, the wiring to other switch u'nits need not be disconnected or deenergized, except insofar as may be desirable to avoid danger of electrical shock.

The accompanying drawings illustrate an embodiment of the present invention, in which,

Fig. 1 is a side elevational view of the rotary switch, it being understood that the switch may be optionally mounted with the rows of switch units spaced horizontally instead of vertically, in which event Fig. 1 will be a plan view,

Fig. 2 is a transverse section along line AA of Fig. 1,

Fig. 3 is an embodiment of a cam, and

Fig. 4 shows a switch locking wheel.

Referring to Fig. 1, there is shown a multi-pole multiposi'tion switch which comprises upper and lower (or right and left) rows 1t) and 11 of aligned switch units each designated generally as 12. As noted above, the switch lit may be mounted with the row of switch units lit disposed at the left and the row of switch units ill. disposed at the right as viewed from the front of the switch, considering Fig. 1 in such case to be a plan view. For convenience in describing the construction and operation of the switch, however, Fig. 1 will be considered to be a side elevational view and the row of switch units it) will be referred to as an upper row which is disposed above the lower row of switch units ll. The switch units 12 of upper row are all secured to an upper mounting bar 13 and. the switch units 12 of the lower row '11 are all secured to a lower mounting bar 14. All of the switch units 12 are substantially identical and fully interchangeable, the switch units 12 of the lower "atent ice row 11 being mounted in inverted position and in vertical alignment with respect to the switch units 12 of the upper row 10.

Each switch unit 12 comprises an insulating body which may advantageously be formed of synthetic resin. Two such insulating bodies 15 without any switching mechanism mounted therein are shown in Fig. 1, one disposed at the left hand end of the upper row 10 of switch units 12 and the other at the left hand end of the lower row 11.

The mounting bars 13 and 14 extend between front and rear end plates 17 and '18, respectively. At their front ends, the mounting bars 13 and 14 are provided with extensions 19 which carry a front cover plate 20. The mounting bars 13: and 14 together with the end plates 17 and 18 constitute the frame of the switch.

Extending parallel to and midway between the mounting bars 13 and 14 is a suitably journaled switch operating shaft 22. Operating shaft 22 is of square transverse cross-section intermediate its ends and extends freely rotatably through cover plate 20. A switch operating handle 23 is fixed to the front end of operating shaft 22 for turning the shaft 22 to various angular positions. A star wheel 24, disposed between front end plate 17 and cover plate Ed is fixed to operating shaft 22 for rotation therewith. Fixed spring pressed detent members 27 cooperate with star wheel 24 to maintain operating shaft 22 in any one of a predetermined number of angularly spaced operational positions determined by the configuration of star wheel 24.

Each switch unit 12 comprises inner and outer terminals designated generally as 25 and 26, respectively. The inner terminal 25 comprises a headed screw 28 which extends outwardly through insulating body 15 and is provided with a threaded shank 29. An L-shaped stationary contact bracket 39 is mounted on shank 29 and is secured against insulating body 15 by means of a nut 32. Washers 33 are loosely fitted over shank 29 and are adapted to receive an electrical conductor (not shown) therebetween which may be made fast by tightening a terminal nut 3d. The free end of contact bracket bears upwardly against a positioning stud 35 formed integrally with insulating body 15. A fixed switch contact 36 formed of suitable electrical contact material is secured to the upper surface of the horizontal arm of contact bracket 30.

The outer switch terminal 26 comprises a hexagonal headed bolt 37 having a threaded shank 38 which passes through the insulating body 15. The bolt 37 is secured by a nut 39 threaded on shank 38 and is provided with washers 49 and a terminal nut 41 for the connection of an external conductor to the outer switch terminal 26 as described above for the inner terminal 25.

A generally horizontally extending movable contact member 43 formed of suitable electrically conductive fiat strip spring material is arranged in the form of a V with its apex pointing toward the left as viewed in Fig. 2. Referring to the switch unit mounted on upper bar 10, the right hand end of the upper arm of the V is bent upwardly and secured under the hexagonal head of 33. The lower arm of the V near its outer end has a movable contact 44 secured to its under surface, the contact 44 being formed of suitable electrical contact material. The movable contact 44 is yieldingly pressed by V-shaped contact spring 43 toward fixed contact 36 for circuit closing engagement therewith.

A bracket 45 is disposed at the apex of V-shaped contact spring 435, its upward movement being limited by a: stud d7 formed integrally with insulating body 15. The bracket 45 comprises spaced downwardly extending ears 4 -8. A pivot pin 49 extends between cars 48. A cam follower 50 is mounted on pivot pin 49. The cam I follower '50 comprises spaced downwardly extending lateral --fianges 52 and an upwardlyarched projecting tongue 53 at its free end. A shaft 54 extends between flanges 52 of cam follower Stland a cam follower roller 55 is *freely rotatably disposed on shafts54 between flanges 52.

As shown in Fig. 2, the roller 55 is disposed in a control recess 57 formed in the periphery of a cam 6%) sothattheroller 55 is unsupported. Contacts 36 and 44 are therefore-in circuit closing engagement. Rotation of cam 60 from the position shown will cause roller 55 to ride upwardly out of the recess 57 and the upper surface of tongue-53 will force the lower arm of contact spring 43 upwardly. Upward movement of -the-apex of V-shaped contact spring- 43 is prevented by stud 47. The free right hand end of the lower'arm of contact spring 43 will therefore be constrained to move upwardly, separating-the contacts 36-and 44 and opening the circuit between terminals and 26.

A series of cams 60 are mounted on operating shaft 22. Each cam comprises a thickened central hub portion 61 and a relatively thin circular peripheral portion 62. The'hubs 61 are no more than one-half as thick as the switch units 12 since the switch units 12 are mounted in two rows and the cams 60 are mounted in a single row. A rectangular slot 63 extends radially inwardly from'the periphery of cam 60 and past its center, terminating in a closed'end portion 64. The outer open end portion of slot'63 is preferably widened as indicated at 65. As shown in Fig. 3, the peripheral portion 62 of cam 60 may advantageously have ridges 67 and 68 formed therein, the ridge 67 being circular and arranged to indicate the-depth of cut for a switch control recess 69 cut in the periphery of the cam. The ridges 68 are in the form of angularly spaced radial lines which converge at the center of the circular periphery of the cam and indicatethe length for a switch control recess. The spacing of the radial ridges 68 conforms with the switch positions as determined by starwheel 24, certain ridges being shown spaced apart and others 15 apart. If

star wheel 24 is provided with twelve teeth, then the 15 spacings will indicate half-way or transient switch positions, these half-way position markings being useful in obtaining make-before-break contact sequences among various switch units. Instead of ridges, grooves may be used, if desired.

Turning now to the features of the invention which provide for independent replacement of switch units and cams, it will'be observed that the upper and lower mounting bars have spaced vertically aligned threaded holes 79 formed therein. Each switch unit body 15 has an openended rectangular recess 71 formed therein which is adapted to receive one of the mounting bars 13 and 14. The recess 71 slidably engages upper and lower surfaces of the mounting bar 13 or 14 while its flat end surface 72 bears against a lateral surface of the mounting bar. The closed end of the recess 71 closely embraces three sides of the mounting bar 13 or 14 which is received therein for positioning the switch unit body fixedly upon the mounting bar. A headed screw 73 comprises a threaded shank which'passes freely through a clearance hole 74 formed in insulating body 15 and engages in one of the threaded holes 70 thereby pressing the flat end surface 72 of recess 71 into engagement with the mounting bar and securing its associated switch unit 12 thereon. By removing its screw 73, any desired switch unit may be individually removed without disturbing any other switch unit, and similarly it may be replaced without disturbing any other switch unit.

The operating shaft 22 has a series of spaced clearance holes 76 formed therein, one hole being provided for each switch unit. Each cam 60 has a radially extending threaded hole 77 formed therein which extends outwardly from the closed end of the slot 63. The end portion 64 of slot'63 closely embraces three sides of operating shaft 22 and centers its associated cam so that its periphery is concentric with the rotational axisof shaft 22. A headed screw 78 comprises a threaded shank portion which passes freely through one of the holes 76 and engages in the threaded hole 77 of its associated cam 69. By removing the screw 78 of a particular cam, it may be slid off from operating shaft 22 through open ended slot 63 without disturbingany other cam and without dismounting the operating shaft 22.

it will be noted that each switch unit body has an inner surface 79 which is shaped to provide clearance for permitting removal of the switch unit 12 past the cam 60 without interference, and similarly to permit removal of the cam without disturbing its associated switch unit. Full independent interchangeability of individual cams and switch units is thus obtained.

It will be noted that the switch mechanism of each switchunit 12 lies forwardly of a centralvertical plane in the case of units of theupper row 10 and rearwardly of this plane in the case of switch units in the lower row 11. This permits the provision of an individual control cam for every unit of each row, the control cams for the upper row 10 being alternately disposed and sandwiched between the control cams for the lower row 11. The open ends of the slots 63 for the control cams 60 associated with the switchunits 12 of the upper row are positioned 180 away from the slots 63 for 'the cams 60 associated with the switch units of the lower row 11. In this way, the full continuous portion of the periphery of each cam is available for switching operation, regardless of whether the switch unit 12 controlled by the particular cam 60 is located in the upper row 10 with its roller pressing downwardly or located in the lower row'll with its roller 55 pressing upwardly.

Each of the individual cams extends longitudinally of the operating shaft 22 for a distance no greater than one-half the distance through which its associated switch 12 extends longitudinally of the mounting bar 13 or 14 to which it is secured. In this way a series of cams 60 may be arrangedon the operating shaft'22 with alternate ones of the cams having the bodies of theirassociated switch units 12 disposed adjacent to one another and all secured to the same mounting bar, 13 or 14, as the case may be.

A locking disc 80'is held fast on operating shaft22 by a set screw 81. The locking disc 80 has slots 82 and 83 (Fig. 4) formed in its periphery. A radially movable locking arm 84 extends through rear end plate 18 and is arranged to enter one of the, slots 82 or 83. under control of suitable mechanism (not shown) such as any electromagnet. If the locking arm 84 enters the relatively narrow slot 82, the switch will be locked in asingle predetermined position. 'If, on the other hand, the locking arm-84 enters the relatively wide slot 83, then the switch may be operated at will within a restricted range of positions.

I have shown what I believe ,to be the best embodiments of my invention. However, it will be apparent to those skilled inthe art that manychanges and'modifications may be made in the specific illustrative embodiments which are herein disclosed without departing from the scope of the invention asdefined in the appended claims.

What is claimed is:

1. In a multi-position multi-contact cam switch, in combination with contact actuating-means and a rotatable operating shaft of rectangular transversecross-sectional configuration for controlling said contact actuating means, the provisionof a unitary control cam having a notched circular periphery arranged toengage and control said contact actuating means and having a slot formed therein, said slot being open at the periphery of said cam and of sufficient width to receive said operating shaft laterally removably therein, said slothaving a closed end portion shaped to closely embrace three sides of saidoperating shaft and position the periphery of.said.cam concentrically with respect to the rotational axis of said shaft, and disengageable fastening means removably securing said cam on said shaft in said concentric position.

2. The combination according to claim 1, wherein the transverse cross-sectional configuration of said shaft is square.

3. In a multi-position multi-contact cam switch, in combination with contact actuating means and a rotatable operating shaft for controlling said contact actuating means, the provision of a unitary control cam having a notched circular periphery arranged to engage and control said contact actuating means and having a slot formed therein, said slot being open at the periphery of said cam and of sufficient width to receive said operating shaft laterally removably therein, said slot having a closed end portion shaped to engage said operating shaft and position the periphery of said cam concentrically with respect to the rotational axis of said shaft, and disengageable fastening means removably securing said cam on said shaft in said concentric position, wherein said cam has a threaded hole formed therein extending outwardly from said closed end of said slot; in which said operating shaft has a transversely extending clearance hole formed therein in alignment with said threaded hole; and in which said fastening means comprises a headed screw having a threaded shank portion which passes freely through said clearance hole and engages in said threaded hole.

4. In a multi-pole multi-position cam switch, in combination with switch frame comprising at least one mounting bar, a rotatable operating shaft extending parallel to and spaced from said mounting bar, and at least one control cam fast upon said shaft, the provision of circuit control means cooperating with said cam for actuation thereby, said control means comprising a body having an open ended recess formed therein of width sufficient to receive said mounting bar laterally removably therein, said recess having a closed end shaped to engage said mounting bar with said control means positioned for cooperation with said cam, and disengageable fastening means removably securing said control means on said mounting bar in said cooperating position, said control means being laterally removable as a unit from said switch with said cam positioned upon said shaft and with said fastening means disengaged.

5. The combination according to claim 4, wherein said mounting bar is of rectangular transverse cross-sectional configuration and in which said recess closely embraces three sides of said mounting bar.

6. The combination according to claim 5, in which the transverse cross-sectional configuration of said mounting bar is square.

7, The combination according to claim 4, wherein said mounting bar has a threaded hole formed therein; in which said recess has a clearance hole formed therein in alignment with said threaded hole when said control means is mounted in said cooperating position; and wherein said fastening means comprises a headed screw having a threaded shank portion which passes freely through said clearance hole and engages in said threaded hole.

8. In a multi-pole multi-position cam switch, in combination with a switch frame comprising two elongated spaced parallel mounting bars, an elongated rotatable operating shaft extending centrally between said mounting bars parallel thereto and spaced therefrom, and at least two control cams each fast upon said shaft and positioned adjacent to each other, each of said cams having a notched circular periphery, the provision of: at least two independent circuit control means, each individually engaging the periphery of one of said cams for actuation thereby, each of said control means comprising a body having an open ended recess formed therein of width sufficient to receive one of said mounting bars laterally remova'bly therein, each recess having a closed end shaped to engage said mounting bar with said control means positioned for cooperation with its associated cam, and a plurality of disengageable fastening means each removably securing one of said two control means on a different one of said mounting bars, each of' said control means being individually laterally removable as a unit from said switch with said cams positioned upon said shaft and with said fastening means disengaged, said bodies of said circuit control means being of substantially identical construction and arranged both in inverted position with aspect to each other and in alignment with each other along an axis perpendicular to the rotational axis of said operating shaft, each of said two cams extending longitudinally of said operating shaft for a distance no greater than one-half the distance through which its associated control means body extends longitudinally along the mounting bar to which it is secured, whereby a series of said cams may be arranged on said operating shaft with alternate ones of said cams having the bodies of the control means actuated thereby disposed adjacent to one another and secured to the same mounting bar.

9. The combination according to claim 8, wherein each of said cams is of unitary construction and has a slot formed therein, said slot being open at the periphery of said cam and of width sufficient to receive said operating shaft laterally removably therein, said slot having a closed end portion shaped to engage said operating shaft and position the periphery of said cam concentrically with respect to the rotational axis of said operating shaft, said switch further comprising a plurality of disengageable cam fastening means each individually securing one of said cams on said shaft in said concentric position, all of said control means being mutually spaced away from each other and from said cams to provide clearance for permitting the individual removal and replacement of any of said cams with respect to said operating shaft and of any of said control means with respect to the mounting bar to which it is normally secured each entirely independently of any other.

10. The combination according to claim 9, in which said operating shaft is of rectangular transverse cross-sectional configuration and wherein said closed end of said slot closely embraces three sides of said shaft.

11. The combination according to claim 10, wherein the transverse cross-sectional configuration of said shaft is square.

12. The combination according to claim 9, wherein said cam has a threaded hole formed therein extending outwardly from said closed end of said slot; in which said operating shaft has a transversely extending clearance hole formed therein in alignment with said threaded hole; and in which said cam fastening means comprises a headed screw having a threaded shank portion which passes freely through said clearance hole and engages in said threaded hole.

13. The combination according to claim 8, wherein each of said mounting bars is of rectangular transverse crosssectional configuration, the corresponding lateral faces of said two bars being parallel to each other, and in which the recess in each of said control means bodies closely embraces three sides of the mounting bar to which it is secured.

14. The combination according to claim 13, in whiEh the transverse cross-sectional configuration of each of said mounting bars is square.

15. The combination according to claim 8, wherein each of said mounting bars has a row of threaded holes formed therein; in which each of said control means bodies has a clearance hole formed therein and in alignment with one of said threaded holes when said control means is disposed in said cooperating position; and wherein said fas- 

